Vulnerability-Lookup

GHSA-JH4V-GFQJ-7RHX

Vulnerability from github – Published: 2026-09-17 14:52 – Updated: 2026-09-17 14:52

Summary

RabbitMQ Java client has frame-level OOM: Math.min(maxInboundMessageBodySize, 0) defeats frame size enforcement

Details

Vulnerability

In AMQConnection.java (line 435-436), after Connection.Tune negotiation, the frame-max limit is set via:

_frameHandler.setFrameMax(
    Math.min(this.maxInboundMessageBodySize, frameMax));

When frameMax = 0 (meaning "unlimited" per AMQP spec), Math.min(67108864, 0) = 0. This value is then passed to Utils.framePayloadLimit(0) which returns Integer.MAX_VALUE (line 77-79 of Utils.java):

static int framePayloadLimit(int frameMax) {
    if (frameMax <= 0) {
      return Integer.MAX_VALUE;
    }
    // ...
}

This completely defeats the maxInboundMessageBodySize protection (default 64MB) at the frame level.

Attack Scenario

A malicious AMQP server (or MITM) sends Connection.Tune with frameMax=0:

Client defaults: requestedFrameMax = 0 (ConnectionFactory.DEFAULT_FRAME_MAX, line 82)
negotiatedMaxValue(0, 0) = Math.max(0, 0) = 0 (line 673-676)
Math.min(maxInboundMessageBodySize, 0) = 0 — 64MB cap defeated
framePayloadLimit(0) = Integer.MAX_VALUE — no frame size enforcement
Attacker sends a single frame with frameSize = 0x1FFFFFFF (~500MB)
Frame.readFrom() (line 135) executes new byte[frameSize] — OOM crash

The frame does not need to be a body frame — method frames, header frames, or heartbeat frames with a crafted size field all trigger the allocation before any content-level check fires.

Root Cause

The AMQP spec uses frameMax=0 to mean "unlimited", but Math.min treats it as the integer value zero. The intent of line 435-436 was to take the smaller of the two limits, but when one limit uses 0-means-unlimited semantics, Math.min always selects the zero, disabling the other limit.

Impact

Default configuration is vulnerable: Both requestedFrameMax (client) and legitimate servers' frameMax in Tune may be 0
Single-frame OOM: One malicious frame triggers up to ~2GB allocation (Integer.MAX_VALUE bytes)
Bypasses existing protection: maxInboundMessageBodySize (introduced to cap allocations at 64MB) is entirely defeated at the frame level
Different from ValueReader OOM: This is a frame-layer allocation in Frame.readFrom(), not a value-layer allocation in ValueReader.readBytes()

Affected Code

AMQConnection.java:435-436 — Math.min with 0-means-unlimited
Utils.java:77-79 — framePayloadLimit(0) returns Integer.MAX_VALUE
Frame.java:135 — new byte[frameSize] allocation site
ConnectionFactory.java:82 — DEFAULT_FRAME_MAX = 0

Suggested Fix

int effectiveFrameMax = (frameMax == 0)
    ? this.maxInboundMessageBodySize
    : Math.min(this.maxInboundMessageBodySize, frameMax);
_frameHandler.setFrameMax(effectiveFrameMax);

This treats frameMax=0 as "use maxInboundMessageBodySize as the cap" instead of "zero".

Severity

8.7 (High)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Maven",
        "name": "com.rabbitmq:amqp-client"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "5.34.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-75516"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-770"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-17T14:52:21Z",
    "nvd_published_at": "2026-09-16T19:17:33Z",
    "severity": "HIGH"
  },
  "details": "## Vulnerability\n\nIn `AMQConnection.java` (line 435-436), after `Connection.Tune` negotiation, the frame-max limit is set via:\n\n```java\n_frameHandler.setFrameMax(\n    Math.min(this.maxInboundMessageBodySize, frameMax));\n```\n\nWhen `frameMax = 0` (meaning \"unlimited\" per AMQP spec), `Math.min(67108864, 0) = 0`. This value is then passed to `Utils.framePayloadLimit(0)` which returns `Integer.MAX_VALUE` (line 77-79 of Utils.java):\n\n```java\nstatic int framePayloadLimit(int frameMax) {\n    if (frameMax \u003c= 0) {\n      return Integer.MAX_VALUE;\n    }\n    // ...\n}\n```\n\nThis completely defeats the `maxInboundMessageBodySize` protection (default 64MB) at the frame level.\n\n## Attack Scenario\n\nA malicious AMQP server (or MITM) sends `Connection.Tune` with `frameMax=0`:\n\n1. Client defaults: `requestedFrameMax = 0` (`ConnectionFactory.DEFAULT_FRAME_MAX`, line 82)\n2. `negotiatedMaxValue(0, 0)` = `Math.max(0, 0)` = 0 (line 673-676)\n3. `Math.min(maxInboundMessageBodySize, 0)` = 0 \u2014 **64MB cap defeated**\n4. `framePayloadLimit(0)` = `Integer.MAX_VALUE` \u2014 no frame size enforcement\n5. Attacker sends a single frame with `frameSize = 0x1FFFFFFF` (~500MB)\n6. `Frame.readFrom()` (line 135) executes `new byte[frameSize]` \u2014 **OOM crash**\n\nThe frame does not need to be a body frame \u2014 method frames, header frames, or heartbeat frames with a crafted size field all trigger the allocation before any content-level check fires.\n\n## Root Cause\n\nThe AMQP spec uses `frameMax=0` to mean \"unlimited\", but `Math.min` treats it as the integer value zero. The intent of line 435-436 was to take the smaller of the two limits, but when one limit uses 0-means-unlimited semantics, `Math.min` always selects the zero, disabling the other limit.\n\n## Impact\n\n- **Default configuration is vulnerable**: Both `requestedFrameMax` (client) and legitimate servers\u0027 `frameMax` in Tune may be 0\n- **Single-frame OOM**: One malicious frame triggers up to ~2GB allocation (`Integer.MAX_VALUE` bytes)\n- **Bypasses existing protection**: `maxInboundMessageBodySize` (introduced to cap allocations at 64MB) is entirely defeated at the frame level\n- **Different from ValueReader OOM**: This is a frame-layer allocation in `Frame.readFrom()`, not a value-layer allocation in `ValueReader.readBytes()`\n\n## Affected Code\n\n- `AMQConnection.java:435-436` \u2014 `Math.min` with 0-means-unlimited\n- `Utils.java:77-79` \u2014 `framePayloadLimit(0)` returns `Integer.MAX_VALUE`\n- `Frame.java:135` \u2014 `new byte[frameSize]` allocation site\n- `ConnectionFactory.java:82` \u2014 `DEFAULT_FRAME_MAX = 0`\n\n## Suggested Fix\n\n```java\nint effectiveFrameMax = (frameMax == 0)\n    ? this.maxInboundMessageBodySize\n    : Math.min(this.maxInboundMessageBodySize, frameMax);\n_frameHandler.setFrameMax(effectiveFrameMax);\n```\n\nThis treats `frameMax=0` as \"use maxInboundMessageBodySize as the cap\" instead of \"zero\".",
  "id": "GHSA-jh4v-gfqj-7rhx",
  "modified": "2026-09-17T14:52:21Z",
  "published": "2026-09-17T14:52:21Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/rabbitmq/rabbitmq-java-client/security/advisories/GHSA-jh4v-gfqj-7rhx"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-75516"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rabbitmq/rabbitmq-java-client/pull/2015"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rabbitmq/rabbitmq-java-client/pull/2016"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rabbitmq/rabbitmq-java-client/commit/6d7c2bfe89796ca34d3531098fb59dd657fea39e"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rabbitmq/rabbitmq-java-client/commit/e7f10bf99aee103dd9f64b3e52a725fc9f9d3763"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/rabbitmq/rabbitmq-java-client"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rabbitmq/rabbitmq-java-client/releases/tag/v5.34.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "RabbitMQ Java client has frame-level OOM: Math.min(maxInboundMessageBodySize, 0) defeats frame size enforcement"
}

CVE-2026-75516 (GCVE-0-2026-75516)

Vulnerability from cvelistv5 – Published: 2026-09-16 18:30 – Updated: 2026-09-18 18:17

Title

RabbitMQ Java client: Frame-level OOM: Math.min(maxInboundMessageBodySize, 0) defeats frame size enforcement

Summary

The RabbitMQ Java client library allows Java and JVM-based applications to connect to and interact with RabbitMQ nodes. Prior to 5.34.0, AMQConnection.start() applies Math.min(maxInboundMessageBodySize, frameMax) after Connection.Tune negotiation even though AMQP defines frameMax value zero as unlimited and ConnectionFactory.DEFAULT_FRAME_MAX is zero. When the client default and server-negotiated value are both zero, the result is passed to Utils.framePayloadLimit(int), which interprets zero as Integer.MAX_VALUE and disables the configured maxInboundMessageBodySize cap. A malicious AMQP server, or a man-in-the-middle attacker able to modify Connection.Tune and inject frames into the connection, can then send an oversized frame of any frame type, causing Frame.readFrom() to allocate a large byte array before content-level validation and potentially terminate the client process through memory exhaustion. This issue is fixed in version 5.34.0.

Severity

8.7 (High)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-18 18:17 UTC

CWE

CWE-770 - Allocation of Resources Without Limits or Throttling

Assigner

GitHub_M mitre root

References

6 references

URL	Tags
https://github.com/rabbitmq/rabbitmq-java-client/…	x_refsource_CONFIRM
https://github.com/rabbitmq/rabbitmq-java-client/…	x_refsource_MISC
https://github.com/rabbitmq/rabbitmq-java-client/…	x_refsource_MISC
https://github.com/rabbitmq/rabbitmq-java-client/…	x_refsource_MISC
https://github.com/rabbitmq/rabbitmq-java-client/…	x_refsource_MISC
https://github.com/rabbitmq/rabbitmq-java-client/…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
rabbitmq	rabbitmq-java-client	Affected: < 5.34.0

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JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-75516",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-18T18:17:15.246486Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
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        "providerMetadata": {
          "dateUpdated": "2026-09-18T18:17:25.002Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "rabbitmq-java-client",
          "vendor": "rabbitmq",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 5.34.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "The RabbitMQ Java client library allows Java and JVM-based applications to connect to and interact with RabbitMQ nodes. Prior to 5.34.0, AMQConnection.start() applies Math.min(maxInboundMessageBodySize, frameMax) after Connection.Tune negotiation even though AMQP defines frameMax value zero as unlimited and ConnectionFactory.DEFAULT_FRAME_MAX is zero. When the client default and server-negotiated value are both zero, the result is passed to Utils.framePayloadLimit(int), which interprets zero as Integer.MAX_VALUE and disables the configured maxInboundMessageBodySize cap. A malicious AMQP server, or a man-in-the-middle attacker able to modify Connection.Tune and inject frames into the connection, can then send an oversized frame of any frame type, causing Frame.readFrom() to allocate a large byte array before content-level validation and potentially terminate the client process through memory exhaustion. This issue is fixed in version 5.34.0."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 8.7,
            "baseSeverity": "HIGH",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
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            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "NONE"
          }
        }
      ],
      "problemTypes": [
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          "descriptions": [
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      "providerMetadata": {
        "dateUpdated": "2026-09-16T18:30:58.983Z",
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          "url": "https://github.com/rabbitmq/rabbitmq-java-client/releases/tag/v5.34.0"
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      "source": {
        "advisory": "GHSA-jh4v-gfqj-7rhx",
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      },
      "title": "RabbitMQ Java client: Frame-level OOM: Math.min(maxInboundMessageBodySize, 0) defeats frame size enforcement"
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  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
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}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

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